Browse Topic: Braking systems

Items (5,482)

Analysis and Elimination of Transient Impact of Rollers in S-cam Brakes

2026-01-5066

To be published on 08/05/2026

S-cam brake is a drum-type foundation brake used in heavy commercial vehicles. It is a safety-critical device; hence, thorough validation of its performance by lab test rigs and field tests is essential. During prototype testing, an unusual impact was observed during dynamic braking at high pressure application, specifically when the brake drum is rotating, after a period of operation of about 10,000 cycles. This phenomenon was then observed even at static braking when the brake drum was at rest. From initial inspection, it is due to the cam roller, which rides on the web-slot provided at the shoe assembly, while the S-cam is rotating and falls back instantly. This phenomenon occurs repeatedly and creates an audible noise, which needs to be eliminated. The study aims to correlate the phenomenon using finite element analysis (FEA) as in a prototype test and to identify the root cause and optimize the design variables. Since the friction coefficient at the cam roller–web interface is unknown after a period of operation, different values of friction coefficient, ranging from 0.1 to 0.8, are iterated and simulated by rotating the S-cam until the braking effort is reached. The dynamic implicit analysis procedure in Abaqus standard is used to simulate this condition. Based on the results, design variables were improved to mitigate the issue. A quick solution, achieved by modifying a minor feature, successfully prevented the fallback behavior and was validated through physical testing. Furthermore, a permanent solution was developed to eliminate both the “ride-on” and “fallback” phenomena by optimizing component dimensions. This FEA methodology helps to validate the design in an initial concept phase itself for future variants. Using this method, even the structural and fatigue performance of braking parts can be validated at a system-level simulation with better accuracy.

Dinesh Kumar, J., Riyaz Mohamed, D., Vasanth Bharath, S., Rajkumar, S., Murugan, S.

Application of a Novel Noise-Reduction Material to Reduce Squeak Noise in Automotive Instrument Panels

2026-01-5065

7/31/2026

In recent years, driven by increasing consumer demands for vehicle aesthetics and perceived quality, automotive instrument panels (IPs) have extensively adopted materials with poor friction compatibility, such as chrome-plated strips and synthetic leather. Concurrently, the engineering requirement for tighter matching gaps between components has significantly escalated the risk of friction noise. Traditional mitigation strategies—such as material substitution, increasing gap clearances, or applying physical isolation—are often difficult to implement due to design constraints, rendering the IP a critical high-risk zone for abnormal noise. This paper proposes a methodology to mitigate squeak noise between polycarbonate/acrylonitrile butadiene styrene (PC/ABS) and its mating counterparts by modifying the viscoelastic characteristics of the PC/ABS base material through the addition of a specialized polymer. Furthermore, a neural network model was established to objectively determine the noise compatibility of these materials. Evaluations of the material compatibility before and after modification demonstrate that adding a specific proportion of the special polymer to PC/ABS significantly improves its friction compatibility with materials such as polyvinyl chloride (PVC) skin. The efficacy of this solution was confirmed through application and verification in a mass-production vehicle.

Liu, Zubin, Cao, Chunyu, Hou, Hangsheng

Research on the Performance Evaluation Method of Intelligent Chassis Vehicles Based on AHP

2026-99-0861

7/30/2026

The comprehensive performance evaluation system for intelligent chassis vehicles comprises multi-level indicators and exhibits certain complexity. In this study, the Analytic Hierarchy Process (AHP) is employed to calculate the weights of indicators across different performance levels. Comprehensive performance is evaluated through the integration of objective indicator assessment and subjective scoring, and the evaluation results of the vehicle’s comprehensive performance are ultimately derived. This work provides a scientific scoring method for the product testing and evaluation of intelligent chassis vehicles.

Wu, Shiyu, Wang, Jingxian, Guo, Ruiling, Liang, Dong, Li, Saisai, Yu, Xuetian

Theoretical Influence of Load Distribution on ADAS Performance in Commercial Vehicles

2026-36-0339

7/30/2026

Advanced Driver Assistance Systems (ADAS) are increasingly integrated into heavy-duty commercial vehicles to improve road safety, mitigate accident severity, and enhance operational efficiency. In the context of braking systems, however, a significant gap remains between system calibration practices and real-world operating conditions, where most evaluations and validations of ADAS and braking performance are conducted under nominal or standardized load assumptions, which fail to represent the wide variability of payload magnitude and distribution typically observed in trucks, semi- trailers, and buses. Variations in vehicle mass and load distribution directly affect braking efficiency, axle load transfer, center of gravity (CG) position, and stability limits, posing critical challenges to both conventional brake systems and brake-related assistance functions. This paper presents an exploratory qualitative study based on a systematic literature review addressing the influence of variable loading on braking performance and the operation of ADAS in commercial vehicles. Scientific publications, experimental investigations, and technical reports from both academia and industry were thoroughly analyzed, with emphasis on service brake efficiency, load-dependent braking behavior, rollover propensity, and the performance of the ADAS systems. The reviewed studies demonstrate that longitudinal, lateral, and vertical CG displacements significantly modify braking force distribution, actuator effectiveness, and stopping distances, particularly under emergency braking and downhill driving conditions. Improper load distribution was consistently associated with reduced braking margins and increased instability risk. The findings further indicate that integrating load-aware strategies into braking control and ADAS calibration can improve braking consistency, reduce component stress, and enhance overall vehicle safety. As a contribution, this work emphasizes the need to incorporate variable load conditions into braking system evaluation, ADAS development, and certification procedures for heavy commercial vehicles, ensuring robust and reliable performance under real operating conditions.

Rubbo, Bruno Tiago, Dacol, Franco De Bastiani, Do Nascimento, Vagner

Maximizing Autonomy, Minimizing Environmental Impact: The Cooperative Regenerative Braking

2026-36-0316

7/30/2026

In conventional braking systems, the kinetic energy of a vehicle is predominantly converted into heat through friction, a thermodynamically inefficient process. This not only causes progressive wear of components but also leads to the release of various materials, including heavy metals and organic compounds. With increasing concern over non-exhaust emissions, the search for innovative solutions becomes imperative. In electrified vehicles (xEVs), regenerative braking emerges as a strategic technology, converting kinetic energy into electrical energy to recharge the battery and extend range. This process not only enhances the vehicle's energy efficiency but also results in reduced frequency and intensity of mechanical brake usage. Consequently, there is a direct reduction in the wear of friction braking components, which translates into a significant mitigation of particulate matter emissions associated with this wear. The optimization of these systems occurs through Cooperative Regenerative Braking (CRB), which intelligently integrates with hydraulic braking. The primary challenge lies in managing the transition between modes to recover maximum energy without compromising safety and driver comfort. This technical paper explores how CRB employs 'torque blending' via advanced ECUs and software to adjust in real-time the proportion of each braking type, aiming for maximum energy recovery in diverse driving scenarios. To verify the effectiveness of this system, practical tests were conducted on a vehicle. The results obtained from these tests were conclusive, demonstrating significant gains in energy efficiency, with an increased battery recharging capacity during decelerations, optimized by the braking system. This improvement in efficiency directly impacts the reduction in the use of the conventional friction brake system and, consequently, a sharp decrease in particulate matter emissions. In this context, the intelligent and cooperative management of regenerative braking is a strategic and fundamental component for building a more sustainable future in vehicular mobility.

Batagini, Emerson, Romão, Bruno

Impacts of Automation and Electrification Trends on Pneumatic Braking Systems of Commercial Vehicles

2026-36-0341

7/30/2026

Historically, the demand for advanced technology, efficiency, and safety has been a primary driving force in the evolution of commercial vehicles, particularly with respect to braking systems. More recently, the increasing levels of vehicle autonomy and electrification have emerged as irreversible trends, significantly accelerating the development of new functionalities and innovative electrical/electronic [E/E] architectures. These advancements are essentially focused on performance optimization, risk mitigation, and enhanced system reliability through the application of functional safety and cybersecurity standards, thereby shaping the current landscape of braking system design. From an efficiency standpoint, braking systems with higher levels of electronic content, functional integration – included with regenerative braking systems - and harmonization have been developed to improve energy efficiency and support global scalability. Concurrently, new system configurations are continuously being introduced to enhance vehicle safety and advanced driver assistance capabilities, in alignment with evolving regulatory requirements and market expectations. This paper evaluates the impacts of automation and electrification on commercial vehicle pneumatic braking systems, focusing on Anti-lock Braking Systems [ABS], Electronic Braking Systems [EBS] and air management platforms. It provides a technical overview of both architectures, assessing their capabilities to meet modern requirements such as integration with advanced vehicle architecture, regenerative braking for electrified applications, and Advanced Driver-Assistance Systems [ADAS] support. The study details the evolution of air management systems, with emphasis on electrified vehicles, including key functions such as air compressor charge control, Air Processing Unit [APU] desiccant regeneration, and electronic control strategies. Additionally, it examines key drivers of braking system evolution, braking system selection considering ADAS regulatory developments, Net Zero strategies, and automation trends. The paper further evaluates compliance with functional safety and cybersecurity standards and assesses the readiness of both platforms for emerging mobility concepts. Finally, it highlights the risks of deploying higher levels of autonomy in heavy-duty towing vehicles when operating with non- ABS semi-trailers, identifying this as a critical area for further investigation.

Guarenghi, Vinícius Mendes, Nicora, Fabio, Pizzi, Rafael Fortuna, Resende, Angelo Roberto Rodrigues, Pinto, Gustavo Laranjeira

Influence of Wheel Stiffness on Brake Drum Deformation in Commercial Vehicles

2026-36-0309

7/30/2026

This study investigates the influence of wheel structural stiffness and wheel configuration (single- and dual-tire) on brake drum deformation in commercial vehicles equipped with pneumatically actuated drum brakes. A comprehensive multi-method approach was adopted, combining on-vehicle measurements, controlled bench testing using two- and three-dimensional optical metrology, and Finite Element Analysis (FEA) of the rear axle assembly. Three- wheel configurations were evaluated: a dual-tire arrangement (Configuration A) and two single-tire designs with distinct stiffness characteristics (Configurations B and C). Radial distortion was quantified using the displacement difference between the bottom and top regions of the brake drum (ΔZ). The results demonstrate that wheel stiffness and the offset between the wheel-disc attachment point and the ground reaction force are dominant factors governing brake drum deformation. The brake drum equipped with dual-tire configurations exhibited minimal ΔZ, whereas the brake drums equipped with single-tire configurations, particularly the least stiff Configuration C, showed pronounced outward radial displacement and increased deformation asymmetry. Design evaluations conducted under the worst-case configuration confirmed these findings, showing an effective reduction in brake drum deformation achieved by increasing the brake drum collar thickness (–36.1%; +6 kg) and by increasing the wheel rim thickness (–27.8%; +4.5 kg).

de Souza, Cassio Belo Clemente, Santana, Flávio Arcanjo, Henze, Steffen, Pulju, Hendrik, Filho, William Manjud Maluf

Feasibility of CFD-thermal-structural simulation based on real braking tests

2026-36-0331

7/30/2026

During the development of mechanical components, engineers use numerical tools as a first step to design, develop, and analyze potential solutions for specific requirements, thereby reducing time- to-market of new components. Furthermore, numerical tools are also highly useful for analyzing components that exhibit failures. For brake discs, numerical analysis must consider not only mechanical behavior but also thermal and fluid dynamic behavior. In this context, as a further step, experimental tests can be performed in test facilities such as dynamometers, where the brake discs are evaluated under different operating conditions to determine their susceptibility to failures such as thermal distortion, judder (hot or cold), squeal, coning, etc. If such failures occur, corrective actions can be implemented using different approaches: a) redesign of the disc and braking system aided by numerical tools; b) tuning of the matching between disc and pad materials; and c) modification of the disc and/or the pad material. Regarding the first approach, the finite element method (FEM) is one of the most important numerical tools, and to obtain reliable results, accurate boundary conditions must be applied. The aim of the study is to demonstrate the feasibility of the CFD-thermal-structural boundary conditions derived from an experimental test performed on a ventilated brake disc assembled in an instrumented vehicle. Firstly, a comparison between an analytical method and the CFD solution was made regarding convective heat transfer coefficient (HTC). The test consisted of 16 main braking cycles from 140 to 0 km/h, conducted under eight different pedal pressure levels. After each main braking, a thermal shock was applied to the disc using water, followed by a secondary braking from 80 to 0 km/h, always with the same pedal pressure. The numerical analysis results showed good agreement with experimental tests in terms of temperature distribution. In addition, axial displacement distribution along the circumference is presented, with emphasis on coning deformation, one of the main triggers for judder.

Bagatini, Pablo Schettert, Viotti, Matias Roberto, Pereira, Leonardo, Tuzzin, Matheus, Titton, Angelo Pradella, Boaretto, Joel, De Leon, Daniel Milbrath

Innovative Friction Modifier for Copper-Free Brake Pad Applications

2026-36-0313

7/30/2026

The development of copper-free brake pads poses a significant challenge because copper plays a critical role in tribofilm formation and friction stability. This study proposes a novel approach using a recycled flake iron oxide material, characterized by high thermal stability and a unique plate-like morphology, as a sustainable alternative. The material acts as a friction modifier, promoting the formation of stable tribofilms and serving either as a copper substitute or a functional additive. Its iron-oxide composition ensures strong compatibility with the counterface tribofilm, enhancing adhesive friction, while its role as a primary plateau contributes to friction stability and reduced wear. Three application scenarios were investigated: (i) copper substitution in Low-Steel (LS) and Non-Asbestos Organic (NAO) formulations, (ii) partial replacement of steel fibers in copper-free LS formulations, and (iii) synergistic use with iron sulfide in copper-free NAO formulations. Tribological performance was evaluated using a tribometer, and worn surfaces were analyzed by SEM and EDS to characterize tribofilm formation. Results demonstrate that the proposed material provides friction stability and wear resistance comparable to copper in both LS and NAO formulations. Partial substitution of steel fibers improved wear resistance by up to 75%, while synergistic addition with iron sulfide further enhanced friction and wear performance in copper-free NAO pads. These findings highlight the potential of this recycled material as a sustainable and effective alternative for copper-free brake pads, offering both environmental benefits and high tribological performance while reducing reliance on critical raw materials.

Jara, Diego Chávez, Lorenzana, Carlos

Development and Validation of a Braking Simulation Model Applied to a 6x2 Vehicle in Compliance with NBR 10966-2

2026-36-0318

7/30/2026

This study presents a comparative analysis of the braking performance of a heavy commercial vehicle under in-gear and out-of- gear conditions, combining experimental tests conducted at 60 km/h with high-fidelity computational simulation. The numerical model incorporates real engine torque, power, and motoring/braking curves, full brake system parameters, dynamic load transfer, tire–road friction characteristics, and ABS actuation. Simulation results were validated against experimental MFDD and stopping distance measurements. The simulation demonstrated a high correlation with the experimental MFDD values (5.3 vs. 5.36 m/s2 in the in-gear condition and 5.6 vs. 5.37 m/s2 in the out-of-gear condition), confirming the robustness of the model. Differences in stopping distance were attributed primarily to the real-world behavior of the ABS and to variability in the road surface friction coefficient. The study concludes that braking with the vehicle in gear provides improved longitudinal stability due to the resistive contribution of engine drag torque, which also reduces the thermal load on the service brakes. Overall, the results reinforce the essential role of simulation as a development, optimization, and certification tool for brake systems.

Junior, Getulio Soares, Canale, Antônio Carlos, de Oliveira, Sergio Henrique Fidelis, Pizzi, Rafael Fortuna

Influence of Aero Enablers on Brake Cooling Performance

2026-36-0317

7/30/2026

Amid growing society concerns about environmental sustainability, fuel consumption has become a key factor in mitigating greenhouse gas emissions. As a result, modern vehicle design increasingly prioritizes aerodynamic drag reduction. However, aerodynamic enhancements can significantly affect brake cooling, since airflow distribution plays a crucial role in braking performance. This study explores the interplay between underbody aerodynamic features and brake cooling efficiency in production vehicles. Three body styles—compact sedan, midsize SUV, and minivan—were evaluated to determine how varying aerodynamic configurations influence airflow around the wheel assemblies. The findings highlight critical trade-offs between aerodynamic optimization and thermal management, offering valuable insights for achieving balanced vehicle development strategies.

Batista, Lorena, Motta, Daniel, Seren, Ericson, Bergel, André, Sarmento, Alisson, Terra, Rafael

Development of an Electronic Braking System Applied to Commercial Vehicles Focused on Improvement of Braking Pedal Feeling and Braking Performance

2026-36-0308

7/30/2026

Embedded electronics are becoming increasingly common in solutions developed for commercial vehicles. Technological advancements enabled the development of electronic solutions that provide braking systems with functions to improve safety, comfort, performance, durability, and cost-effectiveness of wear components. In this context, the electronic braking system, EBS, has become increasingly present in the electronic architecture of commercial vehicles. Considering the functions that can be developed within the electronic braking system, the following stand out: the pedal characterization, which potentially improves comfort and increases the sensation of safety during braking; and the brake force distribution, which can be adjusted to ensure that the vehicle achieves an optimal balance between performance and friction material’s durability. This work consists of the presentation of tests and results of technical activities required to develop an EBS for medium-heavy and heavy-duty vehicles designed for a variety of applications. EBS was developed to prioritize comfort and safety, with optimized braking sensation and performance without compromising the durability of the wear components of the vehicles. Activities started with the experimental determination of the brake factor—a value that transmits to EBS the braking capacity of the truck. In sequence, brake pedal setup was performed based on data extracted from a vehicle equipped with a mechanical braking system and validated by subjective assessment. In addition, the braking force distribution definition started by establishing its target: friction material’s wear equalization or braking performance; went through balancing the mechanical braking power per axle; and finished being validated by data obtained from vehicles in use. Results showed that the implementation of electronic braking systems in commercial vehicles brought several benefits to the product, in particular, improvement of braking feeling when pressing the brake pedal, and in both braking performance and friction material’s durability, which resulted in a better balance between maintenance costs and technical advantages.

Travaglia, Carlos A. P., Rodrigues, André, Rudek, Claudemir, Dias, Eduardo Miranda, Silveira, Juliana

Factors that Influence the Determination of Adhesion Utilization of the ABS in Commercial Vehicles: A Case Study

2026-36-0307

7/30/2026

The anti-lock braking system (ABS) plays a fundamental role in preventing wheel lockup and preserving vehicle steerability and stability during braking. In Brazil, ABS is mandatory for commercial vehicles since 2014, following CONTRAN Resolution 380/11, with the objective of improving traffic safety and reducing road accidents. The performance of an ABS is directly influenced by the characteristics of the vehicle’s braking system, including its pneumatic architecture and mechanical component sizing, which determine brake-force distribution and the frequency of ABS intervention. Regardless of these characteristics, developers must ensure that ABS efficiency complies with applicable regulatory requirements. For performance assessment, NBR 10966 Part 6 establishes procedures for measuring and calculating the adhesion utilization of ABS. Represented by the letter epsilon (ε), adhesion utilization quantifies the relationship between the braking performance achieved with ABS active and that corresponding to the vehicle’s maximum braking capacity without wheel slip. This metric provides an indirect evaluation of system efficiency. This work presents a case study conducted during the development of the ABS for a medium-heavy truck equipped with more than two axles. The study consisted of the analysis of results obtained following the adhesion utilization determination methodology defined in NBR 10966 Part 6, and of the evaluation of its applicability to multi-axle vehicles. Despite the braking system and vehicle configuration meeting all minimum static and dynamic performance requirements, the measured adhesion utilization fell below expectations. This outcome prompted a detailed investigation of both the measurement approach used for this vehicle category and the factors affecting the tire–road friction coefficient, which are independent of the braking system itself. The analysis indicated potential improvements in the test methodology for vehicles with more than two axles and highlighted the significant influence of test-track surface conditions on the results obtained.

Dias, Eduardo Miranda, Rudek, Claudemir, Travaglia, Carlos Abílio Passos

Influence of Modified Fly Ash Content on the Properties of Resin-Based Friction Materials

2026-99-1657

7/24/2026

In this study, five resin-based brake pad samples with modified fly ash contents of 0%, 4%, 8%, 12%, and 16% were prepared to investigate the influence of fly ash content on the comprehensive performance of the friction materials. The tribological properties of all samples were evaluated under temperature conditions ranging from 100 °C to 350 °C, and their overall performance was assessed using five evaluation indices. Based on the AHP-MOORA algorithm, sample F12 exhibited the highest comprehensive weighted score of 0.11, followed by samples F0 and F8 with scores of 0.10 and 0.09, respectively, indicating a slight decline. In contrast, the comprehensive weighted scores of F4 and F16 were relatively low, at 0.05 and −0.01, respectively. Among the five composites, F12 demonstrated the best overall performance, with F0 and F8 ranking next, while F4 and F16 performed poorly. These results suggest that, within a certain range, increasing the fly ash content can enhance the comprehensive properties of the material. However, excessive addition of fly ash may lead to the detachment of harder particles during wear, thereby increasing wear thickness and wear rate.

Li, Xiaobiao, He, Kang, Zhao, Zhuanzhe, Wu, Bo, Sun, Fei

Modal-Constrained Co-optimization Approach of Thermomechanical Performance and Weight for Straight-Ribbed Brake Discs Using Deep Learning

2026-01-5061

7/22/2026

In this study, an efficient method for concurrent thermomechanical performance and weight optimization under modal constraints is proposed to address the coupled design challenges of thermomechanical characteristics (thermal capacity, thermal deformation, and modal) and structural weight in straight-ribbed brake discs. Based on high-fidelity computer-aided engineering (CAE) simulations of brake disc thermomechanical behavior, a neural network (NN)-based surrogate model and a ResNet-guided geometric feature recognition (RGFG) model for automatic modality recognition were developed, and integrated with a particle swarm optimization (PSO) framework for optimal solution exploration. When applied to a passenger vehicle brake disc case study, the surrogate model of NN demonstrates remarkable accuracy: it shows more than 95% agreement with the CAE results in thermal capacity prediction, the prediction accuracy of thermal deformation exceeds 90% compared to CAE results and 83.4% compared to test result, thereby validating the method’s effectiveness. Compared with conventional CAE approaches, the surrogate model of NN achieves a subsecond prediction speed, significantly reducing computational costs. The surrogate model of RGFG achieves a test accuracy exceeding 95%. Furthermore, the proposed optimization framework offers valuable insights for the inverse design of brake discs.

Han, Simiao, Jiang, Daxin, Han, Chao, Wang, Jinda, Sui, Qinghai

Reverse Automatic Emergency Braking (AEB) Testing Summary

J3339_202607 (Current)

7/14/2026

This SAE Information Report provides a broad summary of existing Reverse Automatic Emergency Braking test protocols to help assess whether additional test protocols are needed. Eventually, the task force may develop additional protocols to support testing of Reverse Automatic Emergency Braking systems.

Active Safety and Driver Support Systems Standards Committee

Design and Analysis of Orthogonal Excitation Eddy Current Brake for High-Speed Trains

2026-99-0513

7/10/2026

As high-speed train technology advances, the demands on braking system performance have intensified. Known for their efficiency, reliability, and eco-friendliness, Linear Eddy Current Brakes (LECB) have become a focal point in the research and development of high-speed train braking systems. This paper presents an innovative Orthogonal Excitation Eddy Current Brake (OEECB), which enhances the braking force without modifying the overall dimensions of the conventional LECB. By adding a set of longitudinal excitation coils parallel to the rail surface, the OEECB creates an orthogonal excitation structure that augments the braking force. Initially, this paper outlines the design concept of the OEECB and then analyzes its working principle based on electromagnetic field theory. Subsequently, a finite element solver is employed to numerically model the electromagnetic characteristics of the OEECB. Finally, by comparing the performance differences between the conventional LECB and OEECB, the superiority of the OEECB in enhancing braking performance is demonstrated. The results indicate that under the same excitation current conditions, the OEECB increases the braking force by over 20 % while maintaining a controllable increase in attractive force.

Huang, Liuwen, Zuo, Jianyong, Zhang, Yu

A Transition Curve-Based Design Method for the Recirculation Channel in Internal Recirculating Ball Screws

15-19-03-0011

7/1/2026

Internal recirculating ball screws are widely used as linear motion components in automotive active safety systems, owing to their simple structure and compact size. The recirculation (or deflection) channel is a key feature that distinguishes this type from other ball screw designs. The objective of this article is to investigate this key feature that has been rarely addressed in existing research on internal ball screw. The conventional design method for the recirculation channel involves sweeping the cross-section along the center curve. The center curve is typically defined by various classical equations. These equations are applied in different application scenarios. In automotive braking systems, high loads and strict size constraints place critical demands on both the recirculation channel and its center curve. As a representative best-practice example, the machined channel in the screw is typically employed in this application. This article compares several classical center curve equations and proposes a new general approach based on a family of transition curves. The mechanical analysis identifies the inherent structural characteristics of recirculation channel and develops corresponding design guideline. Furthermore, parameter optimization is performed using MSC ADAMS Multibody Dynamics (MBD) software.

Xia, Xinan, Xia, Yanzhe, Zhao, Tina

Impact of Network-Induced Delays on Autonomous Vehicle Steering Stability

10-10-03-0024

6/25/2026

This article presents a cross-layer framework that integrates realistic vehicle-to-network-to-vehicle (V2N2V) delay characterization with a rigorous stability analysis of automated vehicle steering control. Both constant and network-induced time-varying delays modeled via deterministic bounds are addressed. For constant delays, delay-independent stability regions within the controller gain space are analytically derived. For time-varying delays with stochastic network origins, modeled using deterministic bounds, a refined Lyapunov–Krasovskii functional (LKF) incorporating augmented single- and double-integral terms is constructed. To establish delay-dependent linear matrix inequality (LMI) conditions, a reciprocally convex combination approach is employed to handle the delay interval partitioning, and the second-order Bessel–Legendre inequality is applied to tighten the integral quadratic bounds. The resulting LMI conditions explicitly capture the coupled effects of delay magnitude, delay variation rate, and control gains on closed-loop stability. Simulations of a lane-keeping scenario confirm that the predicted stability boundaries accurately match the closed-loop system behavior. Notably, incorporating a realistic time-varying V2N2V delay profile into the controller design reduces the lateral-state root-mean-square error (RMSE) by over 54% and decreases the settling time by a factor of 10 compared to designs relying on an average-delay assumption. However, high packet loss rates are shown to still induce residual oscillations due to information scarcity. Ultimately, these results elucidate delay-induced instability mechanisms and provide practical guidelines for designing delay-robust steering controllers for connected and automated vehicles.

Li, Jialin, Lu, Jianwei, Wei, Heng, Ao, Di

Reduced Effort Brakes and Reduced Effort Vacuum Powered Brake Backup Systems

J2671_202606 (Current)

6/22/2026

This Information Report relates to a special class of automotive adaptive equipment which consists of modifications to the power brake booster systems provided as original equipment of motor vehicles. These modifications are generically called "Reduced Effort Power Brakes" (REPB) The purpose of the modification is to lower the amount of driver effort required to apply the brakes. Retention of reliability, ease of use and maintainability for disabled drivers, passengers, and the general public is of primary concern. Reduced Effort Power Brake modifications should be qualified by the tests referenced in the Recommended Test Procedure. The tests set forth in that procedure should be applied, and failure of a Reduced Effort Power Brake modification to meet those tests should disqualify the modification from the claim of meeting the specifications of this Information Report. Because this is an Information Report, the numerical values for performance measurements presented in this report and in the accompanying Test Procedure, while based upon the best knowledge available at the time, have not been validated by a testing of the Test Procedure.

Adaptive Devices Standards Committee

On Natural Gas Combustion Split into Diesel Like Architecture of a Compression Ignition Engine Retrofitted for Spark Ignition Operation

2026-37-0029

6/9/2026

In commercial areas that no longer favor diesel engines, such as Europe, it might be interesting to convert an existing compression ignition engine to the spark ignition operation and to use natural gas (NG) because of its advantages: availability of still abundant supplies worldwide and environmental benefits compared to conventional liquid fossil fuels. This paper first presents experimental results on NG combustion inside such a converted engine with diesel-like architecture dedicated to light-duty vehicles and passenger cars. Particularly, our study carried out at the engine test bed revealed that in certain operating points (low speed and load, stoichiometric mixture and rather high spark advance), the combustion is split into two distinct events (first, a fast combustion inside the cylinder and piston bowl and then, a slower combustion occurring outside the bowl-in combustion chamber, in other words, in the squish region), which is not specific to the standard spark ignition engine. This is clearly illustrated by a rate of heat release profile with two peaks. The explanations for such combustion event are also supported by a 3D CFD study showing the in-cylinder NG distribution. The combination of experimental and numerical investigations contributes to the understanding of NG combustion in the diesel like architecture of the converted CI engine when subjected to deliberately extreme conditions, namely non-optimal spark advance setting exceeding the maximum brake torque spark advance.

Clenci, Adrian F., Popa, Robert, Berquez, Julien, Iorga-Siman, Victor, Magheru, Catalin, Punov, Plamen, Niculescu, Rodica

Design-Driven Sustainability of Automotive Components: A Comparative LCA from Conventional to Metal and Composite Additive Manufacturing

2026-37-0037

6/9/2026

The increasing pressure to decarbonize manufacturing systems is pushing industry beyond conventional lightweighting strategies toward material and process paradigms, capable of delivering functional performance with radically lower environmental impact. In this context, polymer-based composite Additive Manufacturing (AM) offers an underexplored yet highly promising pathway for sustainable production of load-bearing components. This study presents a preliminary comparative cradle-to-gate Life Cycle Assessment (LCA) of a Formula SAE brake pedal, assessing the environmental transition from conventional sheet metal fabrication and finishing operations of Aluminum 7075-T6 to additive manufacturing solutions, with specific focus on Carbon-Fiber-Reinforced Polymer (CFRP) composites. Two topology-optimized designs, respectively for Powder Bed Fusion (PBF) in AlSi10Mg and Material Extrusion (MEX) in Polyethylene Terephthalate Glycol with Carbon Fiber (PETG-CF) are compared to conventional fabrication aluminum benchmark. The analysis is integrated in the product and process design following ISO 14040/14044 standards and is implemented using the Environmental Footprint 3.0 methodology within the 3DEXPERIENCE platform. Results outline that Material Extrusion (MEX) composite manufacturing achieves the lowest environmental impact across all evaluated categories. Compared to conventional manufacturing, the PETG-CF solution enables an approximate 50% reduction in Global Warming Potential and an almost complete elimination of mineral depletion. Unlike metal additive manufacturing, which remains constrained by high process energy demand, MEX benefits from low processing temperatures, minimal auxiliary systems, and highly efficient material deposition. Crucially, these sustainability gains are achieved while maintaining functional performance through design-driven topology optimization. AM composite solutions, by merging advanced material science with additive flexibility, may lead to design approaches which cease to be ‘potential’ enablers of sustainable manufacturing for the Industry 5.0 transition.

Dalpadulo, Enrico, Russo, Mario, Apté MD, Raphaëlle, Leali, Francesco

Coordinated Path Tracking and Stability Strategy for Distributed Drive Electric Vehicles Using Model Predictive Control with Dual Feedback Adjustment

10-10-04-0034

6/3/2026

Distributed drive electric vehicles (DDEVs) provide enhanced maneuverability through independent wheel torque control, but coordinating precise path tracking with lateral stability remains challenging under aggressive driving conditions. This paper presents a coordinated control strategy that integrates model predictive control (MPC) for path tracking with a proportional gain controller for stability regulation. The proposed framework adopts a hierarchical design. The path tracking control leverages MPC to compute front steering commands while accounting for vehicle dynamics and preview errors. The stability adjustment uses dual proportional gain controllers to generate an additional yaw moment, which is adaptively balanced through a phase plane coordination mechanism, enhancing yaw stability during path tracking. The generated yaw moment is subsequently distributed to individual in-wheel motors with an optimization torque allocation method, respecting tire force limitations. The effectiveness of the proposed strategy is validated with hardware-in-the-loop (HIL) experiments under a double lane change maneuver. Results show that the coordinated approach improves path following and maintains yaw stability more effectively than conventional methods.

He, Yang, Zhu, Yuzheng, Guo, Ruixin, Zhu, Yueying, Xing, Chao, Liu, Shuangxi, Lin, Yier

Driveline Parking Brake Test Procedure for Medium Duty Vehicles

J2690_202606 (Current)

6/3/2026

This SAE Recommended Practice establishes uniform test procedures for friction based parking brake components used in conjunction with hydraulic service braked vehicles with a gross vehicle weight rating greater than 4500 kg (10 000 lb). The components covered in this document are the primary actuation and the foundation park brake. Various peripheral devices such as application dashboard switches or indicators are not included. These test procedures include the following: a Brake Related Tests 1 Brake Functional Performance 2 Brake Dynamic Torque Performance 3 Brake Corrosion Resistance 4 Brake Endurance with Torque 5 Brake Endurance without Torque 6 Vibration Resistance 7 Brake Ultimate Static Load 8 Brake Lining Wear Adjuster Function b Actuation Related Tests 1 Mechanical Actuator Functional Performance 2 Mechanical Actuator Endurance 3 Mechanical Actuator Quick Release 4 Mechanical Actuator Ultimate Load 5 Spring Apply Actuator Functional Performance 6 Spring Apply Actuator Operating Temperature Range 7 Spring Apply Actuator Endurance 8 Spring Apply Actuator Corrosion Resistance 9 Spring Apply Actuator On-Off Switch 10 Spring Apply Actuator Vibration

Truck and Bus Hydraulic Brake Committee

Heavy-Duty Nonroad Material Handler Electrification Part 2: Energy Efficiency and Performance Evaluation

02-19-03-0016

6/2/2026

Decarbonization efforts achieved through electrification in nonroad mobile machinery can realize a reduction in fuel consumption of more than 20%, thanks to concepts familiar to light-duty passenger vehicles. This case study compares the results of a hybrid-electric material handler to its conventional counterpart, utilizing machine-specific drive cycles presented in part one of this paper series. The hybrid prototype features an extended-range electric vehicle (EREV) powertrain that demonstrated substantial energy efficiency improvements. Specifically, there was a reduction in equivalent fuel consumption of 75% when operating in electric-only mode, and 33% when maintaining the battery by charging with an on-board generator. Together, the efficiency improvements can be extrapolated over a low-intensity, 8-h shift characterized by significant idle time and highly dynamic engine load for a 47% reduction in net energy consumption. Key technologies that led to this improvement included engine downsizing and decoupling, regenerative braking, and an electrohydraulic pump unit with advanced controls. This study explains details of the powertrain architecture and subsystems that were implemented on a demonstration vehicle, control strategies used to meet project goals, and an analysis of energy consumption from testing on a closed course. Also included in this study is a discourse on comparison metrics that can be used for quantifying the energy consumption differences between hybrid-electric and conventional diesel powertrains in nonroad mobile machinery.

Czarnecki, Alexander, Goodenough, Bryant, Worm, Jeremy, Robinette, Darrell, LaTendresse, Phil, Westman, John, Subert, David, Heath, Matthew, Kiefer, Dylan, Black, Andrew

Limit Stability Control for Corner Module Vehicles Based on Hierarchical Hybrid Game

10-10-04-0032

5/18/2026

Corner module vehicles (CMVs) achieve the decoupling of driving, braking, steering, and suspension, significantly enhancing vehicle handling potential, but under extreme operating conditions, the interactions between actuators severely constrain the improvement of vehicle handling performance. In order to mitigate conflicts between subsystems and enhance vehicle handling stability, a hierarchical hybrid game–based limit stability control method for CMVs is proposed in this article. Taking into account the handling potential of subsystems under limit conditions, a Stackelberg leader–follower game is designed by first designating Direct Yaw moment Control (DYC) as the leader and Active Rear Steering (ARS) as the follower. Subsequently, the DYC–ARS and Active Suspension System (ASS) were constructed into a non-cooperative game system, and the Nash equilibrium solution was solved through iteration. The lower-level controllers, respectively, established a tire force distribution model that minimizes the overall tire utilization rate and an active suspension force distribution model that does not affect the vehicle’s pitch, in order to enhance the safety margin of the vehicle under extreme conditions. Finally, the Hardware-in-the-Loop test results proved the effectiveness of the proposed controller.

Peng, Jinxin, Xiao, Feng, Ke, Yuan, Jin, Liqiang

Coordinated Stability Control for Active Rear Steering Vehicles Based on Dynamic Stability Region

2026-99-0713

5/15/2026

To improve the handling stability of four-wheel steering/drive vehicles under complex high-speed maneuvers, this study proposes a coordinated control strategy that incorporates Active Rear Steering (ARS) and Direct Yaw Moment Control (DYC) based on a dynamic stability region. Firstly, a four-wheel steering vehicle dynamics model including lateral motion and yaw motion is established, and the ideal values of the control variables are determined. Secondly, combined with the fuzzy control theory and double-line method, the boundary of the dynamic stability region is obtained in the sideslip angle-sideslip angle rate β−β̇ phase plane, and the vehicle state is categorized into stable, unstable, and critical stable region. Then, A hierarchical control architecture is designed based on the stability boundary. The upper controller comprehensively solves the target rear wheel angle and additional yaw moment through feedforward feedback control; the coordinated control layer allocates control weights according to the stable state of the vehicle; the lower controller optimizes torque distribution through quadratic programming. Finally, the control strategy is validated by MATLAB/Simulink and CarSim co-simulation platform. The results show that the proposed control strategy reduces the RMS values of yaw rate and sideslip angle by 23.1% and 28.5% respectively, significantly improving the handling stability of the vehicle.

Nie, Kehe, Chen, Jin, Wang, Falong, Li, Ren, Bai, Xianxu

Reinforcement Learning-Based Controller for Tiltrotor Aeroelastic Stability Augmentation (Presentation Only)

F-0082-2026-0336

5/5/2026

This study investigated the feasibility of using Deep Reinforcement Learning (DRL) for aeroelastic stability control of a Tiltrotor Aeroelastic Stability Testbed (TRAST) model. The DRL controllers use rotor swashplate inputs to minimize oscillatory wing root bending moments of the tilt rotor model. First, three DRL-based agents including Deep Deterministic Policy Gradient (DDPG), Twin Delayed Deep Deterministic Policy Gradient (TD3), and Soft Actor-Critic (SAC) were investigated to control the aeroelastic stability of the TRAST model throughout a wide range of airspeed including where the whirl flutter occurs. All three agents demonstrated the capability of stability augmentation while the SAC agent demon-strated the most robust performance. Next, the effectiveness of the SAC agent was studied further by training the SAC agent at a certain airspeed and applying the trained agent through the TRAST whirl flutter conditions. Finally, additional tuning of the SAC agent was performed to improve performance further through a hyperparameter optimization framework called Optuna.

Husain, Syed, Floros, Matt, Anusonti-Inthra, Phuriwat, Kang, Hao

The Effect of Initial Foot Position on THOR-50M and THOR-05F Lower Leg Response in a Realistic Vehicle Buck

09-14-01-0008

5/4/2026

This study aims to explore and evaluate the effect of various foot positions on the kinematic and kinetic response of the lower extremity during frontal crashes using a realistic vehicle interior. Frontal impact sled tests were performed with the Test Device for Human Occupant Restraint, 50th-percentile Male (THOR-50M) and Test Device for Human Occupant Restraint, 5th-percentile Female (THOR-05F) anthropometric test device (ATD) in the driver’s seat of a midsize SUV testing buck (with realistic interior components including an instrument panel with steering wheel and steering wheel airbag, seat, three-point seat belt with pretensioner and force-limiter, accelerator pedal, brake pedal, knee airbag, and seat belt retractor pretensioner). Six sled tests were performed in two principal directions of force (PDOF) [three each in frontal (0°) and oblique (−20°) configurations]. The right foot was positioned on the accelerator pedal, fully on the brake, and half on the brake. A single test was conducted with the THOR-05F in an oblique configuration with the foot on the accelerator. Ankle response was analyzed from internal ATD instrumentation. Restraint engagement was found to be consistent across all testing cases. Ankle moment and angle varied based on PDOF and the tested foot condition. Right ankle moment ranged from 70 to −70 Nm in inversion/eversion. Right ankle angles ranged from 37° inversion to 28° eversion. Left ankle moment ranged from 10 to −41 Nm in inversion/eversion. Left ankle angles ranged from 10° eversion to 23° inversion. Differences in lower extremity motion and loading were observed for each testing condition. Placing the foot on the accelerator pedal produced greater ankle moment than either brake pedal condition. Placing the foot on the brake pedal resulted in the highest dorsiflexion angle response. Obliquity increased ankle moment and rotation for both ankles. The United States New Car Assessment Program (US-NCAP) foot position with an oblique PDOF created the highest ankle moment while the in-line brake position in oblique created the highest dorsiflexion rotation. By combining these findings with other efforts focused on naturalistic driving and foot positioning, these results might aid in development of additional testing practices that might enhance our understanding of the lower extremity in nonstandard initial positions.

Noss, Junior, Donlon, John-Paul, Morris, Anna, Samier, Germain, Park, Joseph, Forman, Jason

Braking Performance - Rubber-Tired, Self-Propelled Cranes

J1977_202604 (Current)

4/25/2026

This SAE Standard applies to machines as defined in Appendix A. Some of these machines can travel on-highway but function primarily off-highway.

Cranes and Lifting Devices Committee

Development and Validation of Torque Vectoring and Traction Control Strategies in a FSAE Vehicle Using a Dual-Axle Dynamometer HiL Platform

2026-01-0644

4/7/2026

This study presents the vehicle control optimization of a Formula SAE (FSAE) electric vehicle developed by National Taiwan University Racing Team (NTU Racing), utilizing a dual-axle dynamometer and a real-time Hardware-in-the-Loop platform from Chroma. The novelty of this work lies in the comprehensive system-level validation of independent torque control strategies, namely Torque Vectoring (TV) and Traction Control (TC), implemented directly within the vehicle control unit (VCU), and the high-fidelity simulation of dynamic driving scenarios based on the FSAE circuit. The vehicle features an independently controlled rear-axle, two-wheel drive (2WD) configuration, consisting of two in-wheel motors, self-developed inverters, and planetary gearboxes. During testing, a pre-built CarSim driver model provides throttle, brake, and steering inputs to the VCU via Controller Area Network (CAN) interface. The VCU, in turn, computes the independent torque commands according to the TV and TC strategies, which are then transmitted to the inverters and applied to the motors. The resulting torque output from the planetary gearboxes is measured and fed back into the CarSim vehicle model to simulate the rear wheel dynamics and command the dynamometers at the corresponding rotational speeds. The results show that with the dual-axle platform, the independent torque control strategies could be tuned effectively to improve vehicle dynamics, offering a more quantitative and precise approach for performance optimization compared to conventional Model-in-the-Loop (MiL) evaluations or driver-dependent feedback from track testing.

Hsiao, Tsung-Yu, Chen, Zhi-Ren, Jian, Rong-Wei, Chen, Tai-Hsiang, Wang, Tai-Jie, Hu, Wei-Zhe, Ho, Hui-Ting, Wu, Ting-Yu, Lin, Ting-He, Chiu, Joseph

Embedded Real-Time Control of a Distributed Trailer Propulsion System with Regenerative Braking for Net Neutral Load Towing

2026-01-0065

4/7/2026

Towing imposes substantial efficiency penalties on both battery-electric vehicles (BEVs) and internal combustion engine (ICE) vehicles, reducing range by 30-50%. This paper presents a proof-of-concept embedded control architecture for distributed trailer propulsion that actively regulates drawbar force to reduce towing loads. Unlike proprietary e-trailer systems requiring specialized hardware, the proposed implementation demonstrates feasibility using commercial off-the-shelf (COTS) components and open-source software. The distributed architecture employs dual Raspberry Pi 4B single-board computers communicating via ROS 2 at 20 Hz. The trailer-mounted controller executes a Simulink-generated control node coordinating load cell acquisition (HX711 ADC), motor CAN bus telemetry, and throttle commands to a 5 kW BLDC traction motor powered by a 5 kWh LiFePO4 battery pack. A vehicle-mounted controller logs OBD-II/CAN validation data. The control pipeline implements cascaded EWMA/Hampel digital filtering with intentional phase lag for hitch-force regulation. The system was validated through on-road testing with an ICE towing vehicle pulling a 1,000-lb trailer over standardized 2.1 km segments following SAE J1321 Type II procedures. Preliminary trials demonstrated stable control performance with drawbar force regulation with no oscillatory behavior. Fuel consumption measurements showed promising improvements (9.4% lower fuel consumption in assisted vs. baseline conditions), though limited sample size precludes definitive causal claims. The primary contribution is establishing technical feasibility of cost-effective COTS implementation (USD 5,000 hardware cost) for trailer propulsion control, providing a foundation for expanded validation studies and commercial deployment pathways.

Joshi, Gaurav, Adelman, Ian, Liu, Jun, Donnaway, Ruthie

Technical Outlook on the Potential of HVO and Biodiesel Blends for Cleaner Combustion

2026-01-0316

4/7/2026

The increasing need to decarbonize the transport sector is accelerating the adoption of renewable and low-carbon fuels such as Hydrotreated Vegetable Oil (HVO) and biodiesel as sustainable substitutes for fossil diesel. These fuels are evaluated as drop-in solutions requiring no engine recalibration, enabling immediate GHG emission reduction in existing diesel fleets. This study experimentally investigates the combustion, performance, and emission characteristics of a turbocharged common-rail two-cylinder diesel engine (Kohler LWD 442 CRS) operated with conventional fossil Diesel, pure HVO (Hydrotreated Vegetable Oil), and an HVOB20 blend (80% HVO and 20% biodiesel produced from waste cooking oil and animal fats). Tests were carried out under steady-state conditions at the DIIEM Engine Laboratory of Roma Tre University. The analysis focused on in-cylinder pressure evolution, brake power, brake specific fuel consumption (BSFC), and both regulated and unregulated emissions. Regulated species include carbon monoxide (CO), nitrogen oxides (NOₓ) and particulate number concentration (PNC > 23 nm, PMP-compliant), while unregulated emissions cover non-methane hydrocarbons (NMHC), formaldehyde (HCHO), nitrous oxide (N₂O). CO and NMHC are key indicators of incomplete combustion: CO results from partial oxidation of carbon during fuel burning, and NMHC represents the fraction of unburned hydrocarbons excluding methane. Both pollutants decreased markedly with renewable fuels, indicating a more complete oxidation process promoted by HVO’s paraffinic composition and FAME’s oxygenated nature. Experimental results show that HVO and HVOB20 slightly increase brake torque and reduce BSFC compared with fossil diesel, despite their lower density and heating value. Combustion remained stable across all operating conditions, with negligible variations in ignition delay and pressure rise rate. NOₓ emissions were comparable or marginally higher at medium engine speeds, likely due to faster ignition and elevated combustion temperatures. Unregulated species such as HCHO and N₂O decreased or remained negligible with increasing renewable content, while PNC and count mean diameter (CMD) were significantly reduced, confirming cleaner combustion and reduced soot formation. Overall, both HVO and HVOB20 demonstrated improved combustion efficiency and emission performance while ensuring full engine operability without calibration adjustments. These findings confirm the technical viability of renewable diesel fuels as immediate, drop-in solutions for reducing GHG emissions.

Zaccai, Martina, Chiavola, Ornella, Palmieri, Fulvio, Verdoliva, Francesco

Vehicle Test Platform with Experimentally Correlated Tire Model for Torque Vectoring Control

2026-01-0622

4/7/2026

This paper presents a testing platform for the development of lateral stability control systems in independent motor electric vehicles (EVs). A 10 degree of freedom (DOF) vehicle simulation and a radio control test vehicle are constructed to enable controls validation scalable to full size vehicles. These vehicle simulations, or ‘digital twins’, have been widely adopted throughout the automotive industry due to their lower operating costs and ease of implementation. Virtual models are not perfect representations of reality, however, and physical testing is still necessary to validate systems for use in the real world. This is especially true when testing safety-critical features such as stability control. As a result, a simulation environment working in conjunction with a test vehicle represents an optimal hybrid approach. In this work, a high fidelity vehicle model is constructed in the Matlab/Simulink environment. To capture the effect of suspension, the digital twin is capable of modeling all angular and linear degrees of freedom of the vehicle body. The vehicle model must also estimate wheel forces during high-sideslip maneuvers. The Pacejka Magic Formula is used for its accurate representation of tire behavior in highly transient driving scenarios. This vehicle model describes the behavior of a physical vehicle. For this purpose, a 1/5 scale radio controlled vehicle with independent rear wheel propulsion is designed and assembled. All physical parameters of the test vehicle required by the vehicle model are estimated through direct measurement or estimation through test maneuvers. Magic formula coefficients are estimated from GPS, inertial, and odometry measurements collected throughout defined test maneuvers. Vehicle model behavior is then benchmarked against the test vehicle. An S-curve maneuver is performed in simulation and experimentation to ensure accuracy and consistency across transient and steady state behavior. In future work, focus will turn to creating an ADAS control system which re-stabilizes a vehicle after a collision using torque vectoring.

Petersen, Nicholas Conner, Robinette, Darrell

Quantifying the Impact of Towing on BEV Energy Use: Instrumented On Road Testing and Chassis Dynamometer Reproduction

2026-01-0431

4/7/2026

Electrification is rapidly entering all vehicle classes, including light- and heavy-duty trucks designed for heavy towing capabilities. Still, the quantitative impact of towing on battery-electric vehicle (BEV) energy use and range remains under-characterized. We conducted controlled towing tests with a Ford F-150 Lightning using two trailers of different sizes and varying payloads to isolate aerodynamic and mass effects and to span the full range of towable payloads within the vehicle’s rated capacity. The vehicle was instrumented at the CAN bus level, capturing motor power, torque, speed, and related internal signals from different control modules. On-road testing consisted of repeated back-and-forth passes on level, straight road segments at set speeds focusing on highway operation, where aerodynamic drag is stronger and real-world towing use cases occur. From these data, we extracted road load equations and dynamometer coefficients for each trailer combination, then reproduced equivalent conditions on a four-wheel drive chassis dynamometer across several standard cycles. Results were consistent across runs, showing a significant increase in the vehicle’s overall energy consumption and a corresponding range penalty. Additional impacts on vehicle systems due to towing, including thermal management of the motors and battery, were quantified. Dynamometer tests of varying characteristics (highway, urban, steady state speeds and accelerations) allow isolation of specific behaviors in functions like regenerative braking operation and torque-split strategy. Dynamometer results aligned with on-road measurements, enabling repeatable laboratory evaluation of towing scenarios. These findings provide a validated methodology and dataset to quantify towing impacts on BEVs, inform range prediction and route planning, support labeling and consumer guidance, and characterize sustained, high load real world operation of vehicle components.

Timermans Ladero, Inigo

Backlash Evasion Strategy for Enhancing Vehicle Cornering Performance

2026-01-0640

4/7/2026

This study presents a torque distribution control strategy for EVs with e4WD powertrain to overcome the trade-off between ensuring vehicle acceleration and deceleration responsiveness and mitigating backlash shock in the driving system. The deterioration of the drivability which occurs from the intrinsic hardware characteristics of the drivetrain is prevented by designing a response-priority drive mode in which neither front or rear motor torque is allowed to change its sign. Instead, in such drive mode, the front motor torque is only allowed to perform regenerative braking while the rear motor torque is only allowed to produce positive acceleration torque. In order to avoid sacrificing the maximum acceleration by applying such strategy, the mode transition function is implemented as well. In addition, in order to prevent backlash impact due to drivetrain compliance, variable offset torque based on drivetrain compliance model is evaluated in real time and applied to each motor command generation strategy. The enhancement of vehicle drivetrain responsiveness directly leads to improved track driving performance, particularly for the neutral-balance phase during harsh cornering. The effectiveness of the suggested driveline torque distribution method is verified using an actual vehicle driven on the race track, and the vehicle responsiveness followed by track driving performance indices are numerically assessed for comparison.

Oh, JIWON, Lee, Ho Wook

Machine Learning for Predicting Rotor and Brake-Fluid Temperatures in Hill-Descent Events

2026-01-0159

4/7/2026

High thermal loads on brake systems during extended descents followed by vehicle soak pose significant safety and durability risks. Excessive rotor or fluid temperatures can cause loss of braking efficacy, fluid degradation or evaporation, thermal fade, and accelerated component wear. This study uses time-history data of brake-disc and fluid temperatures which were collected during controlled hill-descent events with subsequent soak periods, where the vehicle is parked in a wind protected area. Besides the rotor and brake fluid temperatures, environmental conditions were recorded (ambient temperature, humidity, wind speed and direction) and the vehicle and brake specifications are known (rotor/caliper geometry, pad material, vehicle aerodynamic configuration and mass). 126 test runs from a dedicated vehicle program are used, each providing time-history records that form the basis of our analysis. From these records we extract phase-specific samples (descent and soak phase) and engineer compact descriptors — start and peak temperatures, environmental factors, rolling statistics and contextual metadata to represent each event. We develop and evaluate machine-learning regression and neural-network models to predict the disc and brake-fluid temperatures occurring during the descent and across the soak phase. Cross-validation is done to ensure generalization to unseen descent events. Models are evaluated with mean absolute error (MAE) and bias diagnostics. The predictive models enable early warning of critical temperature spikes and support design and operational decisions (cooling design, allowable profiles and optimization). By delivering fast temperature estimates, they reduce reliance on computationally expensive CFD during early design, while CFD and experiments remain for final validation. We present workflow, model performance and uncertainty characterization.

Poojari, Uday Kumar, Westphalen, Jan, Venugopal, Narayana

Predictive Assessment of Drum Brake Squeal Utilizing Advanced Time-Domain CAE Synthesis

2026-01-0221

4/7/2026

With the growing trend of electric vehicles (EVs) incorporating regenerative braking systems, many compact SUVs, including hybrids and EVs, still utilize drum brakes on the rear wheels to strike a balance between cost, performance, and durability. Drum brake squeal remains a complex and persistent challenge in the field of vehicle noise, vibration, and harshness (NVH). This issue stems from dynamic instability caused by time–dependent friction forces. Traditional linear modal analysis has been used to study the mechanisms behind drum brake squeal, focusing on harmonic vibrations in large–scale models. However, these methods often fail to accurately correlate with real world behavior due to the presence of extra, non-physical modes. To address this, time–domain analysis approaches have been explored, incorporating detailed friction models and contact mechanics. These methods consider different root causes for high and low–frequency squeal and have shown promising results in accurately predicting brake squeal behavior when validated against experimental data.

Song, Gavin, Kazimierczyk, Stanislaus, Vlademar, Michael, Venugopal, Narayana

Study of Automatic Emergency Braking Effects on Human and Surrogate Passengers

2026-01-0556

4/7/2026

The influence of modern Automatic Emergency Braking (AEB) on the head and neck behavior of the occupants in a vehicle continues to be an active area of research. Occupant kinematics and kinetics were evaluated using a vehicle equipped with a pedestrian AEB system. The vehicle was tested in several different scenarios with speeds between 15 and 45 mph. Two instrumented 50th-percentile male Hybrid-III Anthropomorphic Test Devices (ATD) were positioned in certain seats of the vehicle, while minimally instrumented human volunteers occupied the remaining seats. Displacement transducers and video analysis were utilized to capture the kinematics of each occupant. The findings of this study indicate that in AEB-only events with belted-occupants, the test vehicle did not result in any occupant motion that would have placed the occupants out-of-position (OOP) had an impact occurred immediately following the AEB event. This means that when evaluating real-world AEB events, it may not be necessary to analyze and model properly seated and restrained occupant kinematics prior to an impact event when only AEB occurs. Consistent with the published literature, the kinetic results continue to show that the belted occupant exposure is significantly below any accepted injury criteria and is comparable to routine activities of daily living. Tests were also completed in two seating configurations with unbelted ATDs to evaluate the difference in vehicle braking (if any) and the excursion differences when unbelted. The study found greater excursion for unbelted ATDs compared to that of belted volunteers and provides a sample of unbelted ATD kinematics via AEB activation.

Bartholomew, Meredith, Dahiya, Akshay, Russell, Caleb, Morr, Douglas, Castro, Elaine, Nguyen, An

A Study of Federal Motor Vehicle Safety Standard 126 and 136 Test Procedures on a Class 5 Vehicle

2026-01-0616

4/7/2026

Federal Motor Vehicle Safety Standards (FMVSS) 126 and 136 are standards imposed on four of the eight recognized road vehicle classes in The United States. These standards make it mandatory for Electronic Stability Control modules (ESC) to be mounted to Class 1,2,7, and 8 vehicles. These modules strategically activate the vehicle brakes via the Antilock Brake System (ABS) to limit the recorded yaw rate and lateral displacement of a vehicle during an extreme cornering maneuver such as a sudden swerve to avoid an obstacle on the road. The two aforementioned FMVSS mandates also specify three different driving maneuvers that are conducted to profile and analyze ESC module performance. There is now an interest in creating a new FMVSS that makes ESC modules mandatory for Class 5 vehicles. The purpose of this paper is to analyze how one specific Class 5 vehicle’s ESC module performed when subjected to the two test procedures that correspond to FMVSS 126 and 136. As will be seen, the vehicle’s ESC performed quite well for the FMVSS 126 testing criteria and not as well with the FMVSS 136 testing criteria. The details of these results should both be considered if and when a new FMVSS ESC mandate is to be produced. To aide in the creation of such a mandate, additional experimental and simulation data will be necessary from other Class 5 vehicles. Simulated driving maneuvers with an accurate vehicle model will prove valuable in this pursuit. The results of such simulations will be discussed and the value that they bring will help to expedite the formation of the proposed FMVSS that covers these vehicles.

Cazares, Richard Isaac, Guenther, Dennis, Heydinger, Gary

Modular 3-D Lumped-Parameter Thermal Network for Thermal Estimation of Permanent-Magnet Synchronous Motors in Electromechanical Braking Systems

2026-01-0136

4/7/2026

As electric intelligent vehicles advance, drive-by-wire systems are increasingly adopted, and the thermal reliability of electromechanical brake (EMB) motors—the key actuators—remains safety-critical. Under stalled-rotor operation, unequal DC currents are typically applied to the three phases, producing nonuniform winding heating. Conventional thermal models can miss the associated tangential heat-transfer effects, increasing the risk of phase-wise end-winding hot spot. This paper analyzes EMB motor thermal behavior under stalled-rotor conditions using a modular 3-D lumped-parameter thermal network (LPTN). First, a standardized tooth module with external interfaces is developed. Its internal parameters are informed by experiments and computational fluid dynamics (CFD) and identified via particle swarm optimization (PSO), allowing the module to be encapsulated for reuse. Next, based on the machine topology, a minimal motor is derived and multiple tooth modules are interconnected through common nodes to form a modular 3-D LPTN that resolves radial, axial, and tangential heat-flow paths. Finally, a stepwise, weighted PSO is applied—module level followed by system level—to calibrate the full network. The tooth-module abstraction also enables rapid network assembly, and the boundary-cooling and loss-allocation modules can be updated to accommodate different cooling architectures and heating patterns while retaining the same internal formulation. Bench tests with inhomogeneous three-phase heating, validated against three-phase end-winding thermocouple measurements, show that the proposed model predicts temperatures more accurately than existing LPTNs. These results indicate that explicitly accounting for tangential heat exchange can improve temperature prediction for EMB motors under stalled-rotor duty and provides a reusable template for other concentrated-winding machines subject to nonuniform thermal loading.

Duan, Yanlong, Xiong, Lu, Wang, Xinjian, Zhuo, Guirong, Zeng, Jie

Development of a Lightweight and Quick-to-Install Pedal Robot for Unmanned Chassis Dynamometer Testing

2026-01-0197

4/7/2026

As the adoption of electric vehicles continues to accelerate, the demand for their development and testing using chassis dynamometers has also increased significantly. Compared with internal combustion engine vehicles, chassis dynamometer testing for electric vehicles typically requires test durations several to several dozen times longer, resulting in substantially increased labor requirements. In addition, low-temperature testing is often required, further intensifying the workload associated with vehicle testing. To address these challenges, this study developed and evaluated a pedal robot designed to enable unmanned and automated testing. The pedal robot developed in this study weighs only 12 kg and can be installed within a few minutes. It is, to the authors’ knowledge, the world’s first pedal robot that mimics human driving behavior by using a single foot to operate both the accelerator and brake pedals. Unlike conventional driving robots, the actuators of the proposed system do not require direct mechanical attachment to the vehicle pedals, allowing for rapid installation. Furthermore, the robot is mounted on the driver-side floor, eliminating the need for attachment to the seat structure. The pedal robot features three degrees of freedom driven by three motors and employs artificial intelligence to recognize the shape and position of pedals across different vehicle models, thereby enabling automated test initiation without manual adjustment. The performance of the pedal robot was evaluated under UDDS, HWFET, and WLTC driving modes, and the results were analyzed in accordance with the SAE J2951 standard. Comparative evaluations demonstrated that the pedal robot achieved superior speed-tracking performance relative to that of an experienced human test driver. The developed pedal robot is currently being utilized for vehicle certification testing of electric and other vehicles at the Mobile Environment Research Center of the National Institute of Environmental Research in Korea. This paper presents a detailed analysis of the corresponding experimental results.

Lee, Daeyup, Kang, Ji Myeong, Jo, Yechan, Choi, SeongUn, Shin, Jaesik, Kim, Jongmin, Kang, Keonwoo

Research on Electro-Hydraulic Compound Braking Coordinated Control Strategy Based on Sliding Mode Control

2026-01-0631

4/7/2026

Hydraulic braking torque and motor braking torque are the main sources of braking torque of new energy vehicles. Hydraulic braking converts vehicle kinetic energy into heat dissipation, and motor braking converts vehicle kinetic energy into electric energy to achieve energy recovery. In the process of vehicle braking, when the wheels tend to lock, it is easy to cause vehicle instability, which seriously threatens the safety of driving. Therefore, how to coordinate the braking torque of the two braking systems to ensure the vehicle braking safety and energy recovery efficiency is still an urgent problem to be solved. In this paper, the electric vehicle equipped with electro-hydraulic compound braking system is taken as the research object, and the electro-hydraulic compound braking coordinated control strategy considering the general braking state and emergency braking state is proposed. Firstly, a 3-DOF vehicle longitudinal dynamic model is established according to the vehicle dynamic characteristics. Secondly, in the general braking state, the braking torque of the front and rear axles is optimally distributed with the energy recovery as the optimization objective. Then, in the emergency braking state, taking the vehicle braking safety as the optimization target, based on the sliding mode control method, by adjusting the braking torque of the front and rear axles to make the actual slip ratio follow the expected slip ratio, the optimal control of the vehicle slip ratio is carried out. Finally, the electro-hydraulic compound braking torque distribution is carried out on the braking torque of the rear axle. Simulation and real vehicle test results show that, compared with the conventional rule-based coordinated control strategy, the proposed strategy significantly reduces the fluctuation of vehicle slip ratio and improves the energy recovery efficiency by at least 7.7%, so the vehicle safety and energy recovery efficiency are significantly improved.

Zhao, Binggen, Zhao, Bingquan, Zhang, Xiaoyang, Wang, Zhenfeng, Zhao, Gaoming, He, Chengkun, Zhang, Junzhi, Ma, Changye

Prediction of Pressure Pulsation in Brake Line Considering Wave Propagation Characteristics of Fluid Contained in Flexible Hose for Automotive Hydraulic Brake System

2026-01-0225

4/7/2026

Brake pulsation noise caused by fluid-borne vibration, which is generated by pressure pulsations from the pump in the Electronic Stability Control (ESC) modulator, occurs when the control brake function is activated under various driving conditions, such as Adaptive Cruise Control (ACC) and regenerative-friction brake coordination. This noise is particularly noticeable in Battery Electric Vehicles (BEVs), where the background noise from the power source is lower than that of internal combustion engine vehicles. The simulation of pressure pulsations in the brake system requires the excitation force of the pump built into the ESC modulator, the characteristics of valves, and the characteristics of the flexible hose; however, it is extremely difficult to determine these parameters with high accuracy from the design specifications. For this reason, in this study, the pump and valves were experimentally identified, while the flexible hose was represented by a three-element Voigt model to describe its viscoelastic properties. The pressure pulsation prediction model of the brake line was constructed by formulating the characteristics of all hydraulic components using four-pole matrix equations consisting of pressure, flow rate, and impedance, along with the continuity equation. This paper describes the method for creating a prediction model of pressure pulsation, the measurement results of the transfer matrix of the flexible hose, the modeling and parameter identification method of the flexible hose, and the accuracy verification results from a bench test of a brake system equivalent to an actual vehicle. Since a high-accuracy prediction model has been constructed, by predicting the pressure pulsation at any position in the brake line for any pump rotation speed, it can be utilized for designing the pump rotation speed that achieves both braking performance and brake pulsation noise reduction, and for examining bending and clamp positions of the brake line that avoid the amplification of excitation force.

Koike, Yohei, Komada, Masashi, Yano, Masahiro, Yoshioka, Nobuhiko

An Adaptive Brake Force Allocation Strategy for Rear-Wheel Driven EVs

2026-01-0636

4/7/2026

Due to changed requirements compared to conventional propulsion concepts, electromobility demands new and innovative strategies for energy-efficient vehicle motion control. For example, the challenge in purely rear-wheel drive (RWD) electric vehicles (EVs) is to achieve a maximum of regenerative braking power in order to increase energy recovery and to ensure, that this does not impair the braking stability. Within this conflict between energy efficiency and braking dynamics, it is necessary to design an intelligent strategy to optimise recuperation. This paper presents such a strategy, which improves an existing approach formerly presented by the authors, but specifically optimised to overcome weaknesses. The previous approach had two major limitations: First, the efficiency map of the in-wheel machines (IWMs) was not considered. Second, there was no possibility of switching flexibly between different brake force distributions to guarantee both, maximized recovery potential and high braking stability, in fulfilment of legislative requirements. The new strategy addresses these shortcomings by introducing a speed-dependent torque limit for the electric drive motors to avoid inefficient operating and uses two independent factors to manipulate the brake force distribution along the axles and vary the distribution between the actuators. In addition, various scenarios were analysed and incorporated into the new strategy in order to achieve optimal torque distribution in every driving situation. The developed approach was implemented into a real vehicle and extensively tested in driving trials on closed-off terrain and on public roads. The results of the investigation demonstrate the ability to ensure stable vehicle control and a 45.3 % increase in energy recovery in comparison to the established benchmark.

Mitsching, Thomas, Heydrich, Marius, Ivanov, Valentin

Characterizing Regenerative Braking of the Tesla Model 3 Using Chassis Dynamometer Testing

2026-01-0453

4/7/2026

Regenerative braking has a strong influence on the energy efficiency and drivability of battery-electric vehicles. This study establishes an empirical baseline analysis under controlled conditions of the regenerative braking behavior of the 2020 Tesla Model 3 to support the interpretation of on-road performance and serve as a reference for subsequent testing and analysis. The tests were performed on a four-wheel-drive chassis dynamometer at Argonne National Laboratory, combining Multi Cycle Testing (MCT) to simulate real world driving patterns (city, highway) with coast-down tests to isolate periods where the motor is operating in regen mode and compare the behavior across different parameters. Vehicle data was collected from the vehicle using taps in the Controller Area Network (CAN) bus as well as a high-resolution power analyzer. The vehicle displayed the highest efficiency during simulated city driving conditions (3.62 miles/kWh followed by highway (3.40 miles/kWh) and aggressive (2.53 miles/kWh) conditions, though aggressive driving showed the highest energy recovery. Regenerative energy recovery was most efficient in the 10 – 30 mph range, with the rear motor regenerating all the energy while the front motor used a small amount of power. Standard regen mode achieved 57% greater deceleration during coast down compared to Low Regen mode and showed a much lower variability during different simulated uphill and downhill conditions. Standard mode collected more energy than Low mode in all cases apart from simulated downhill tests where Low mode performed better. These results provide an overview of the Tesla Model 3 regenerative braking behavior and delineate operating regimes that maximize efficiency and quantify trade-offs between deceleration stability and energy recovery across driver-selectable modes. The results provide a rigorous, reproducible baseline and measurement protocol that can enable cross-vehicle benchmarking, validate vehicle/software-in-the-loop models, and inform future controller calibration and the design of on-road and track experiments

Pierce, Benjamin Branch, Di Russo, Miriam, Das, Debashis, Zhan, Lu, Stutenberg, Kevin

Research on Vehicle and Longitudinal Tire Model Parameters Identification Based on Electro-Mechanical Brake System

2026-01-0634

4/7/2026

The Electro-Mechanical Brake (EMB) system is a novel type of brake by wire systems with independently controllable characteristics. This system aids in the decoupling analysis of the vehicle and actuator dynamics, thereby improving the accuracy of parameter identification. Therefore, this paper proposes an innovative parameter identification method for vehicle parameters and longitudinal tire model parameters, based on the characteristics of the EMB system and onboard sensors. First, based on the wind resistance and rolling resistance coefficients obtained from the vehicle coasting conditions, a decoupled constant clamping force sequence braking condition for the front and rear axles is designed by integrating the characteristics of the EMB actuator and vehicle dynamics. This approach enables the identification of vehicle and nonlinear longitudinal tire model parameters, significantly improving the accuracy of parameter identification. Next, considering the nonlinear characteristics of the longitudinal tire model, a factorial experiment is conducted to analyze the impact of the Particle Swarm Optimization (PSO) optimization algorithm parameters on the identification process from three perspectives: iteration count, computation time, and optimal function value. Furthermore, the effectiveness of three PSO variants: the Compressed Factor PSO (CF-PSO), the Adaptive Weight PSO (AW-PSO), and the Hybrid PSO (H-PSO), was investigated for identifying the nonlinear characteristics of the longitudinal tire model. Finally, through data simulation and real-vehicle experiments on both high-adhesion and low-adhesion roads, the effectiveness and accuracy of the proposed vehicle parameter and longitudinal tire model parameter identification method based on EMB system characteristics are verified through a comprehensive evaluation of multiple indicators, and the method’s validity is further confirmed using data backfill and model benchmarking.

Huang, Jiayi, Cheng, Yulin, Zhuo, Guirong, Le, Qiao, Wei, Wei, Shu, Qiang

Optimal Control Analysis of Minimum-Time Maneuvers for Vehicles Recovering from Instability

2026-01-0218

4/7/2026

Vehicles may enter highly unstable dynamic states due to lateral collisions, sudden loss of grip, or extreme steering disturbances. When such instability arises in congested road sections where obstacle avoidance is required, the safety risk to both the ego vehicle and surrounding traffic escalates significantly. In such scenarios, the vehicle must not only regain stability but also navigate the roadway in the shortest feasible time to prevent secondary collisions. This paper investigates the minimum-time maneuver of a vehicle starting from an unstable dynamic condition and constrained to travel within prescribed road boundaries. A single-track vehicle model with combined-slip nonlinear tire model is employed to capture the vehicle dynamics under high slip conditions. Phase-plane analysis is conducted to reveal how control inputs reshape the system’s vector field and influence the possibility and speed of stability recovery. An optimal control problem is formulated to compute the minimum-time control sequence subject to both dynamic and kinematic constraints, actuator limits and road boundary constraints. The optimal control problem accounts for both stabilization and rapid progression through the constrained road segment. Simulation results on straight and curved road sections show that the minimum-time maneuver consistently exhibits a two-stage structure. The vehicle initially undergoes a stabilization phase, characterized by spiral convergence in the (β, r) phase plane. After stability is restored, the optimal maneuver transitions into the second phase where the vehicle follows the minimum-time trajectory dominated by the road geometry. The findings suggest that, in emergency scenarios, stability recovery should be prioritized before attempting aggressive avoidance or cornering maneuvers.

Leng, Jiatong, Yu, Liangyao, Wang, Yongxin, You, Weijie, Li, Ziang, Jin, Zhipeng

A Cooperative AFS/DYC Lateral Stability Control for FWDIEV Based on Dissipative Energy Method

2026-01-0619

4/7/2026

To enhance the lateral stability of four-wheel-drive intelligent electric vehicles (FWDIEV) under extreme operating conditions, this paper proposes a cooperative control strategy integrating active front steering (AFS) and direct yaw moment control (DYC) based on dissipative energy method. A nonlinear three-degree-of-freedom vehicle model is established to analyze the evolution of the vehicle state phase trajectory. A quantitative lateral stability index is constructed using dissipative energy to accurately evaluate the vehicle’s lateral dynamics. Utilizing dissipative energy and its gradient information, a time-varying stability boundary is defined under dynamic constraints, and adaptive weighting coordination between the AFS and DYC systems is designed to achieve coordinated control of front steering angle and additional yaw moment. A feedforward–model predictive control (FF-MPC) framework is developed, in which a feedforward module generates compensation based on driver intent to improve system responsiveness, while the model predictive controller predicts real-time vehicle states and optimizes the front steering angle and yaw moment control inputs. This enables cooperative tracking of the yaw rate and sideslip angle, effectively suppressing lateral motion errors. Furthermore, an optimal torque distribution strategy is formulated with the objective of maximizing tire–road friction utilization, incorporating constraints such as tire load rate and motor output capability to prevent wheel slip and improve handling stability. The effectiveness of the proposed control strategy is validated through both CarSim/Simulink co-simulation and real vehicle tests under typical maneuvers such as high-speed double lane change on various road surfaces. Results demonstrate that the proposed method significantly reduces tracking errors in yaw rate and sideslip angle compared to conventional MPC strategies, thereby enhancing lateral stability and ensuring driving safety under extreme conditions.

Zhao, Kun, Zhao, Zhiguo, Wang, Yutao, Xia, Xue, Chen, Xi, Hu, Yingjia

Inertial Pedal Displacement and Brake Switch Activation in Frontal Crash Events

2026-01-0541

4/7/2026

This paper presents research into the inertial displacement of brake pedals and the subsequent activation of brake light switches during crash events. In certain scenarios, such as multiple-impact crashes or crashes with pre-impact interactions such as curb strikes or sideswipes, inertial forces alone may generate sufficient brake pedal movement to trigger the brake switch, activating the brake lights. Such signals may be recorded by an Event Data Recorder (EDR) or observed by witnesses and incorrectly interpreted as an indication of intentional driver braking. To investigate this phenomenon, HYGE sled tests were performed using brake pedal assemblies and associated components from a Toyota Tacoma pickup truck and a Cadillac DeVille passenger sedan. The assemblies were subjected to acceleration pulses simulating a frontal impact, with high-speed video used to capture brake pedal displacement and brake light activation. The tests demonstrated that inertial loading from a pulse with a delta-V (change in velocity) as low as 12 mph could result in momentary brake light activation due to pedal displacement from inertial forces. Increasing the magnitude of the acceleration pulse produced greater displacement of the brake pedal and extended the duration of the brake light activation. An example is presented that demonstrates inertial pedal movement in a full-scale vehicle test conducted by striking a curb, which resulted in brake light activation with a delta-V considerably less than 12 mph. Additionally, a field survey of 50 passenger vehicles found that the brake switch activation threshold ranged from 0.25 to 0.56 inches of pedal travel for 80% of the vehicles measured. These findings indicate that relatively small crash accelerations and durations can produce sufficient inertial pedal movement to activate brake lights and that only minimal pedal displacement is required in most vehicles.

Walker, James, Duran, Amanda, Barnes, Daniel, Osterhout, Aaron, Clayton, Aidan

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